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Where is the True North Pole?

The north pole is the top of the earth, and the south pole is the bottom, of course...

except that the earth is kind of a ball, and they don't really have tops and bottoms. Granted,

the earth isn't exactly spherical and it's spinning through space - spinning about an

imaginary axis of rotation. One of the points where that axis goes through the earth, right

here in the arctic ocean, where the Russians planted their flag on the sea floor in 2007,

is called the north pole... or rather, it's the "geographic" north pole. Because, just

like there are different definitions for what a "year" is, there are different north poles.

For example, compasses don't point to the geographic, or spinning-top, north pole. They

point to the MAGNETIC north pole, which is incidentally a magnetic south pole since opposites

attract. The magnetic north (actually south) pole and south (actually north) pole are an

electromagnet caused by swirling convection currents in the earth's liquid iron outer

core. These currents are heavily influenced by the rotation of the earth, so the magnetic

field they generate roughly aligns with the earth's axis of rotation - but not precisely,

and not unchangingly. A hundred years ago, the magnetic north pole was located in northern

canada - over 2000km south of the geographic north pole. And it's been moving consistently

north-west since then, currently sitting in the middle of the Arctic Ocean 450km south

of the geographic north pole, and drifting about 55 kilometers closer to Russia each

year.

What's more, the magnetic south pole is not on the exact opposite side of the earth from

the magnetic north pole - it drifts around in a somewhat independent fashion and is currently

20° closer to the equator than magnetic north! Such is the nature of magnetic fields generated

by confusingly swirly molten iron deep inside the earth.

But if you imagined, instead, that there were just a giant, perfect bar magnet inside the

earth, then that perfect bar magnet would point towards the GEO-magnetic north pole.

Which is currently located in Ellesmere Island, Nunavut, Canada. This pole, together with

the geomagnetic south pole which IS on the exact opposite side of the earth, represents

the general, overall trend of the earth's magnetic field, especially as it extends into

space. So while it's not at all useful for compass navigation on the earth's surface,

it does heavily influence the paths of solar wind particles that cause the aurora - that

is, the northern lights. Beautiful.

In short, the north pole's whereabouts depend on what you care about. The earth spins like

a top around the "geographic" north pole, compasses point to the "magnetic" north pole

(which is actually a magnetic south pole), and the northern lights are strongest in a

ring around the "geomagnetic" north pole (also a magnetic south pole).

All three north poles move, too - the magnetic and geomagnetic poles change quite drastically,

but even the geographic north pole moves up to ten meters a year as the earth wobbles

on its axis due to seasonal air pressure differences across the globe, melting ice caps, and so

on.

Assuming that the Russians planted their flag exactly at the geographic north pole in August

2007, not once since then has it been exactly at the pole - it was as far as 12 meters away

in 2009 and as close as 20 cm in 2010 - right now it's about 3 and a half meters away. Basically,

the earth is doing the biggest, slowest, pole dance ever around the Russian flag.